Apparatus for dehumidifying air



March 23, 1948.

APP

w. H. FREYGANG 2,438,120

ARATUS FOR DEHUMIDIFYING AIR Filed Jan. 27, 1944 9. mw @W GttomegPatented Mar. 23, 1948l UNITED STATES PATENT oFFlcE 2.438.120 APPARATUSFOR DEHUMIDIFYING AIR Walter H. Freyung. Essex Fells, N. J., assigner toKidde Manufacturing Co., Inc., a corporation of Delaware ApplicationJanuary 27, 1944, Serial No. 519.840

8Claims.

lower than the temperature of the outside air.

for instance, during warm periods such as the summer months. It is alsowell known that during the aforementioned warm periods temperature andrelative humidity are important factors in obtaining body comfort, forthe reason that the human body is, to an appreciable extent, influencedby the temperature of the surrounding air, which serves to evaporate theperspiration from the body, the rate at which the perspiration isevaporated from the body into the air being influenced by the relativehumidity of the air. Generally, in order to produce a sense of comfortto the average person at rest. a temperature from 68 to 70 F., and arelative humidity of 50 per cent (about 4 grains of water vapor percubic foot of air) is considered to be a very satisfactory condition ofthe air. If the temperature is lower than '70 F., the relative humidityshould be higher than 50 per cent, or, if the temperature is higher, therelative humidity should be lower, so that the same eifect of comfort tothe person is provided.

In the majority of instances, in rooms or enclosures having atemperature of '10 F., the relative humidity has been discovered to beconsiderably less than 50 per cent and, in some instances, as low as 28per cent. This very low relative humidity has the effect of imparting tothe person a feeling of chilliness even though the temperature may besubsequently increased from '70 to 78 or 80 F. This chilly or coolingeiect is the result of the rapid evaporation of moisture from the skin,the rapid evaporation being due to the low vapor pressure of theatmosphere. Conversely, where extremely high relative humidity exists, atemperature of 70 F., might feel oppressively hot to the person.

From the foregoing, it will be apparent that, in buildings wherein therooms or enclosures are heated by the atmosphere during warm periodswhen high temperatures and high relative humidities are prevalent, it isdesirable to provide means for controlling or dehydrating the air in amanner whereby an optimum satisfactory relation of humidity totemperature may be established under prevailing temperature conditionsin order to protect the room structures and contents against theaccumulation of moisture thereon and/or to gain the most in the way ofbody comfort. This desire is fulfilled by the present invention.

An object of the invention is to provide means constituting adehumidifying unit or system so constructed or arranged as toautomatically effect dehumidication of air within a room or enclosureand in a manner to establish an optimum satisfactory relation ofhumidity to temperature within the room or enclosure.

Another object of the invention is to provide a unit of the foregoingdescribed character which is simple in construction, durable in use,eilicient in operation, economical in manufacture, and which lendsitself to ready movability.

With the above and other objects in view, as will hereinafter appear,the invention consists in the combination, and arrangement of partshereinafter set forth and illustrated in the accompanying drawing, fromwhich the several features of the invention and the advantages attainedthereby will be readily understood by those skilled in the art.

The single gure of the drawing is a schematic view, partly in section,illustrating an embodiment of the present invention.

The dehumidifying unit or system, illustrated in (the sectional view of)the drawing, is adapted to be utilized within a room or other enclosurefor dehumidifying the air therein, and comprises a base 8 and an airtunnel or cabinet 9 mounted on the base, having an open front endsection I0 and top, bottom, side and rear walls II, I2, I3

y and I4, respectively.

Acabinet is provided with an evaporator I6 of a refrigerating unit, theevaporator being spaced from the rear wall to provide an air passage I1between the wall I4 and the evaporator.

The evaporator I6 is provided with the usual evaporator coil I8, orthelike, having one end connected to a compressor I8 of therefrigerating unit by means of a pipe 28 and having the opposite endconnected, by means of a pipe 2 I, to one end of a coil 22, or the like,of a condenser 23 of the unit, the condenser being disposed within thefront end section I of the cabinet. The opposite end of the condensercoil 22 is connected, by means oi' a pipe 26, to the compressor I8, thelatter being driven by a motor 26 mounted on the base 8 below thecabinet 9.

An expansion valve 24 is provided in the pipe 2| between the compressorand the evaporator and has a connection 21 connected to a temperatureresponsive device (not shown) disposed with- In the pipe 2U, thereby tooperate .the expansion valve in accordance with temperature variationsof the refrigerant issuing from the coil I3.

The'cabinet has mounted therein, between the evaporator and thecondenser, air propelling means 28, for instance, a motor 29 equippedwith a fan 30 to eilect circulation of air through the cabinet from theinlet opening I to and through the front end section Ill from which theair is discharged into the room for circulation therein. I'he air thuscirculated through the cabinet ilows between the coils of the evaporatorand condenser and establishes, within the cabinet, an air stream havinga relatively cold zone between the evaporator and condenser and arelatively warm zone in front of the condenser due to the air streambeing subiected to the cooling and heating inuences of the evaporatorand condenser, respectively.

'Ihe circulation of air through the cabinet is controlled by means of ashutter 3| in the cabinet between the evaporator I6 and air propellingmeans 28, the shutter 3i being provided with adjustable slats or vanes32 connected to a thermostatically operated control means 33, disposedoutside of the cabinet, by means of linkage 34, whereby the slats areadapted to be positioned for controlling the passage of air through theshutter 3i.

The top wall I I of the cabinet is provided with an inlet conduit 35through which unconditioned or room air may enter the cabinet for apurpose hereinafter described. The passage of air into the cabinet,through the conduit 35, is also controlled by a shutter 36 extendingacross the conduit 3T and provided with adjustable slats or vanes 31. Athermostatically responsive control device 33 is mounted in the frontend section III of the cabinet and in front of the condenser 22, wherebyair discharged through the condenser influences the operation of thedevice 38, the latter beine connected to the slats 31 by linkage 38 foreii'ecting adjustment of the slats to control the passage of air throughthe conduit 35.

Below the evaporator I6. the cabinet is formed with a sump 40 forreceiving water from the coil I8 occasioned by condensation of moisturethereon. the sump having a drain pipe 4I connected thereto whereby theWater may be drained from the sump for convenient disposal.

If desired` the front section of tbe cabinet may be equipped with aglass-wool air iilter 42 to remove dust and impurities from the airdischarged therethrough.

A thermostat 45, operated by temperature variation of the air stream, ismounted within the cabinet, adjacent the upper front Seiion Q fconductor 41, while the other terminal of saidl switch is connected toone terminal of the compressor motor 26 by a conductor 48. The otherterminal of the compressor motor 26 is 'connected to the other inputconductor 48 of the power source by a conductor 60. Both conductors 46and 48 of the power source are connected to the fan motor 28 byconductors 6| and 62, respectively. Outside of the cabinet, adjacent theopening I6, there is mounted a humidity 'control device, for instance, ahygrostat 63 of the type provided with an electrical switch (not shown),the latter being operated by the hygrostat for making and breaking anelectric circuit upon operation of the hygrostat. The terminals of thehygrostat switch are connected in circuit with the conductor 43 of thepower source and between the latter and the conductors 41 and 5I asdiagrammatically illustrated in the drawing.

In operation, assuming the switches of the thermostat 46 and hygrostat63 are closed, refrigerant is pumped from the compressor into thecondenser 23 and from the latter into the evaporator I6 through theexpansion valve 24. From the evaporator I6, the refrigerant is returnedto the 'compressor I8 thus completing the cycle of circulation. Duringthe circulation, the refrigerant serves to heat the condenser coil 22and cool the evaporator coil I8 in the usual manner. Coincident with thecirculation of the refrigerant, air is propelled through the cabinet bymeans of the fan 30 and subjected to the cooling and heating influencesof the evaporator and condenser coils as it passes therethrough wherebysaid air is dehydrated in accordance to a predetermined value, as willhereinafter become apparent.

As the warm or unconditioned room air passes through the evaporator coilI 8. ice will form on the lower portion of the coil and will pre-cooland deflect the air outwardly within the passage I1 where it passesthrough theupper portion of the coil, moisture condensing on the coilbeing discharged to the sump for drainage therefrom.

In order to guard against both the upper and lower portions of theevaporator coil becoming blocked by ice and precluding the flow of airthrough both portions, the thermostat 46, adjacent the upper portion oi'the coil is set to operate at a, predetermined temperature, for instance35 F. When the temperature of the air, passing through the upper portionof the coil, is lowered to the aforementioned value, the thermostat 46operates its switch to break the circuit through the conductors 41 and48 with the result that the compressor is shut down, thus, stoppingcirculation of refrigerant through the evaporator coil I8 and permittingthe temperature of the coil to be raised, by the room air passingtherethrough, to a sumcient degree to preclude any appreciable amount ofice from collecting on the upper portion and blocking the same, therebypermitting air to pass through the upper portion of the coil at alltimes during the circulation oi the air through the cabinet.

In order to cool and dry the air to obtain a humidity value comparablewith the temperature of the room and under certain conditionshereinafter made apparent, the rate of now or the.

air through the evaporator is controlled by the thermostatic controlmeans Il, the latter being operatively connected to the shutter 3|. Theslats 32 of the shutter 3| are pre-adjusted with respect to thethermostatic control means ll and in a manner whereby operation of thecontrol means n serves to position the slats I2 for controlling the rateof ilow of the air through the evaporator Il. For example, at a roomtemperature of 80 F.,.the slats of the shutter are adjusted with respectto the thermostatically operated control means 3l until the air passingthrough the evaporator and shutter reaches a definite rate of flow andwith the air having a desirable relative humidity, for instance, fiftyper cent, and a desirable temperature, for instance 40 F., it beingunderstood that the rate of ilow of the air with a temperature of 40 F.,is sufllcient to meet the cooling requirements of the condenser.

Assuming that the foregoing factors are the optimum operatingrequirements of the unit and that the same is controlled by the roomtemperature and the rate of flow of the air through the evaporator andcondenser, it will be apparent that should the room temperature vary,for example, rise to 100 F., it would be necessary to compensate forthis differential in temperature in a manner to fulfill the optimumoperating requirements in order to maintain the efciency of the unit.The invention, in order to compensate for this differential, comprehendsthe use of a compressor of sufllcient capacity to meet the additionalcooling load thus presented to the evaporator and at the same timepermit the same rate of flow of the air through the condenser to bemaintained and with the temperature of 40 F. When the evaporator isloaded, the expansion valve 24 operates, through the medium of theconnection 21, to increase the circulation of refrigerant through thecoil I8 to meet the increased cooling demand of the coil.

Separately from or conjointly with the foregoing, the invention alsocomprehends decreasing the rate of flow of the air through theevaporator in order to maintain the evaporator at optimum temperature tocool the air to the desired 40 F. This decrease in the rate of the ilowof the air through the evaporator is accomplished through the operationof the control means 33, in response to the rise in room temperature,which positions the slats 32 in a manner to reduce the rate of flow ofair through and from the evaporator I6.

When the rate of flow of air through the evaporator is reduced andmaintained at a temperature of 40 F., it may not meet the optimumcooling requirements of the condenser due to the reduced rate of flow ofthe air passing therethrough. When this condition prevails, the airpassing through the condenser will be heated to such an extent as tocause operation of the thermostatically operated device 38, the latterbeing set for operation at the highest temperature conducive to propercooling of the condenser coil. Upon operation of the device 38, theslats 31 will be adjusted in a manner to permit sufilcient room air toenter the cabinet through the conduit 35 and mix with the dehumidifledair in the cabinet and thereby provide sufcient volume of air with a lowenough temperature to meet the cooling demands of the condenser coil.

As the air passes through the relatively hot to at least its originaltemperature and serves as assenso 6 a cooling medium for the condensercoil. in this respect. the unit diiiers from an air cooler for thereason that it functions as its own condensercooler. thereby eliminatingthe use of cold outside air or water as a condenser-cooler. When theroom air, passing through the opening Il, reaches a predeterminedrelative humidity, the humidity control device or hygrostat I3 operatesto open its switch and thus break the circuit through the conductor Ilresulting in the stopping of both the compressor and fanmotors 2l and20, respectively. A predetermined change in the relative humidity servesto operate the hygrostat to close its switch whereby the unit isoperated as heretofore described.

.In view of the foregoing description, it will be seen that the presentinvention provides an improved unit for dehumidifying the air in roomsor other closed spaces. The unit is constructed of a minimum number ofparts and is compact in assembly to facilitate movability. The unit isrugged in construction and can readily withstand any rough usage towhich it may be subjected.

As various changes may be made in the form,-

construction and arrangement of the parts herein, without departing fromthe spirit and scope of the invention and without sacrificing any of itsadvantages, it is to be understood that all matter herein is to beinterpreted as illustrative and not in any limiting sense.

It is also to be understood that the following claims are intended tocover all the generic and speciiic features of the inventionA hereindescribed, and all statements of the sc-ope of the invention which, as amatter of language, might be said to fall therebetween.

I claim:

1. In a dehumidifier, a housing having oppositely disposed inlet andoutlet openings to permit air to be dehumidiiied to be circulatedthrough said housing, a refrigerating unit associated with said housingand having an evaporator and a condenser disposed in said housingadjacent said inlet and outlet openings, respectively, air propellingmeans for propelling air through said evaporator and said condenser, ashutter mounted in said housing between said condenser and saidevaporator for controlling the rate of flow of the air through saidevaporator, a thermostat mounted outside of said housing and connectedto said shutter for operating the latter, said housing being providedwith an inlet conduit between said shutter and said condenser foradmitting air into said housing to increase the rate of iiow of the airthrough said condenser, means for controlling the admission of air intosaid housing through said conduit and including a thermostat operated bythe temperature of the air passing through said condenser, and dualcontrol .means responsive to the temperatures of the air outside andinside of said housing for controlling the operation of saidrefrigerating unit.

2. In a dehumidifier, a housing having oppositely disposed inlet andoutlet openings to permit air to be dehumidifled to be circulatedthrough said housing, a refrigerating unit associated with said housingand having an evaporator and a, condenser disposed in said housingadjacent said inlet and outlet openings, respectively, air propellingmeans mounted in said housing between said evaporator and said condenserfor propelling air through said evaporator and said condenser, a shuttermounted in said housing between said airpropelling means and saidevaporator for controlling-the rate of flow of 7 the air vthroughsaid-evaporator. a therm mounted outside of said housing-and connectedto said shutter for operating the latter, said housing being providedwith an inlet conduit between said shutter and said condenser foradmitting air into said housingto increase the rate of ilow of the airthrough said condenser, means for controlling the admission ot air intosaid housing through said conduit and including a thermostat operated bythe temperature of the air passing through said condenser, a thermostatmountedin said housing adjacent said evaporator for controlling theoperation of said refrigerating unit, and hygrostatlc means mountedoutside of said housing adjacent said inlet opening for con.-trollinggthe operation of said refrigerating unit and said 'airpropelling means.

3. A dehumidifying unit comprising a compressor, a tunnel having an endinlet, an end outlet and an intermediate inlet, an evaporator in thetunnel between said inlets, means for controlling the ilow ci' airthrough said end inlet, means for controlling the flow of air throughsaid intermediate inlet, a condenser in the tunnel between saidintermediate inlet and said outlet, means in the tunnel between saidcondenser and said intermediate inlet for drawing air through saidinlets, means completing a reirigerating system including meansconnecting said evaporator and condenser through said compressor, meansfor controlling the operation of said compressor in accordance with thetemperature of air adjacent to said evaporator, means responsive topredetermined temperature conditions in a space to be affected by theunit for actuatingsaid end inlet ilow control means, means operative inaccordance with a temperature condition of said condenser for actuatingsaid Aintermediate inlet iiow control means, and means responsive tohumidity effects of air in the space for controlling the operation ofsaid compressor and said air drawing means.

4. A dehumidifying unit comprising a compressor, a tunnel having an endinlet, an end outlet and an intermediate inlet, an evaporator in thetunnel between said inlets, means in the tunnel between said evaporatorand said intermediate inlet for controlling the ilow of air through thetunnel, means in the tunnel for controlling the air entering saidintermediate inlet, a condenser in the tunnel between said intermediateinlet and said outlet, means in the tunnel for drawing air into thetunnel as controlled by said end and intermediate inlet flow controllingmeans and directing the drawn air against said condenser and throughsaid outlet, means completing a refrigerating system including meansconnecting said evaporator and condenser through said compressor, meansfor controlling the operation of said compressor in accordance with thetemperature of air adjacent to said evaporator, means responsive topredetermined temperature conditions in a space to be aiIected by theunit for actuating said end inlet flow control means, means responsiveto temperature change in the air-adjacent to said condenser foractuating said intermediate inlet flow control means, and meansresponsive to humidity eiects of air in the space for controlling theoperation of said compressor and said air drawing and directing means.

5. A dehumidifying unit comprising a compressor, a tunnel having an endinlet, an intermediate inlet and an end outlet, an evaporator in thetunnel between said inlets, means between said evaporator and saidintermediate inlet for controlling assenso thetlowoi'airfromsaidendinlet.meansiorcon trolling the'air from said intermediateinlet.' a condenserinthe tunnel between said intermediate inlet and saidoutlet, means in the tunnel for drawing air through said inlets, meanscompleting a refrigeratlng system including means connecting saidevaporator 'and said condenser through the compressor, said completingmeans also including an expansion valve connected across the evaporatorfor operation in accordance with temperature variation 'of therefrigerant from the evaporator, means for controlling the operation ofthe compressor in accordance with the temperature of air'adiagent tosaid evaporator, means responsive to predetermined temperatureconditions in a space to be aii'ected by the unit for actuating said endinlet iiow control means, means responsive to temperature change in airadjacent to the condenser for actuating said intermediate inlet iiowcontrol means, and means responsive to humidity efrects of air in thespace for controlling the operation of said coinpressor and said airdrawing means.

6. A dehumidifying unit comprising a compressor, a tunnel embodying anend outlet, an intermediate inlet and an opposite end wall having a lowinlet opening, an evaporator in the tunnel next to said end wall havingan under portion opposite said low inlet opening and an upper portionopposite the upper portion of said end wall, a condenser in the tunnelnext to said outlet, means for forcing air through said intermediateinlet and said low inlet opening to said outlet, means for controllingthe air entering said low inlet opening, means for controlling airentering said intermediate inlet, means completing a, refrlgeratingsystem including means connecting said evaporator and said condenserthrough the compressor, means responsive to room temperature foractuating said low inlet air controlling means, means responsive totemperature at the condenser for actuating said intermediate inlet aircontrolling means, means responsive to temperature at the upper part ofthe evaporator for controlling operation of thev compressor, and meansresponsive to room humidity for controlling operation of the compressorand of said air forcing means.

7. In a dehumidiiying unit adapted to be placed in a room, the air ofwhich is to -be dehumidified, the combination of a refrigerating systemincluding compressor means, evaporator means, expansion valve means andcondenser means; air ow conduit means having inlet means adapted toreceive air from the room and outlet means adapted for delivering theair to the room, said conduit means containing said evaporator and saidcondenser means with said evaporator means in upstream air flowcooperation with said condenser means; air draft generator means foreffecting said flow; means automatically operative during the operationof the unit for controlling the ilow of refrigerant: means responsive toroom temperature for controlling the room dehumidifying effects of saidevaporator means; and means for maintaining the temperature of saidevaporator means at substantially a predetermined value.

8. In a portable humidifying unit adapted to be placed in a room, theair of which is to be dehumidiiled, the combination of a cabinet, arefrigerating system in said cabinet including an evaporator and acondenser, a tunnel extending through said cabinet having inlet andoutlet means in communication with the room, said evaporator beingpositioned in the tunnel next to condenser.

WALTER H. FREYGANG.

REFERENCES CITED The following references are of record in the ille ofthis patent:

Number UNITED STATES PATENTS Name Dato Newton Oct. 1, 1941 McGrath Sept.22, 1942 Shipley Dec. 22, 1931 Parcaro Sept. 12, 1939 Number Ramsey June8, 1943 FOREIGN PATENTS Country Date France Nov. 23, 1933 France Jan.24, 1918

